better fix for [3028370] GL get error should return a valid error if no context is bound.
it turns out that we cannot return INVALID_OPERATION from glGetError() because the
GL spec says that it must be called in a loop until it returns GL_NO_ERROR.
now, we always return 0 from GL functions called from a thread with no
context bound. This means that glGetError() will return NO_ERROR in this case,
which is better than returning a random value (which could trap the app in a loop).
if this happens in the main thread of a process, we LOG an error message once.
Change-Id: Id59620e675a890286ef62a257c02b06e0fdcaf69
diff --git a/opengl/libs/GLES_CM/gl.cpp b/opengl/libs/GLES_CM/gl.cpp
index d71ff76..ee29f12 100644
--- a/opengl/libs/GLES_CM/gl.cpp
+++ b/opengl/libs/GLES_CM/gl.cpp
@@ -114,6 +114,7 @@
"ldr r12, [r12, %[tls]] \n" \
"cmp r12, #0 \n" \
"ldrne pc, [r12, %[api]] \n" \
+ "mov r0, #0 \n" \
"bx lr \n" \
: \
: [tls] "J"(TLS_SLOT_OPENGL_API*4), \